The stable negative charge of an inactive neuron is known as the:

• A. action potential
• B. depolarization phase
• C. resting membrane potential
• D. threshold potential

Answer: (C)

Verified step by step guidance

1. Understand the context: The problem is asking about the stable negative charge of an inactive neuron. This is a fundamental concept in neurobiology related to the electrical properties of neurons.
2. Define the key term: The 'resting membrane potential' refers to the electrical charge difference across the neuron's plasma membrane when the neuron is not actively transmitting a signal. This potential is typically negative inside the cell relative to the outside.
3. Explain the mechanism: The resting membrane potential is maintained by the sodium-potassium pump (Na⁺/K⁺ ATPase) and selective permeability of the membrane to ions. The pump actively transports 3 Na⁺ ions out of the cell and 2 K⁺ ions into the cell, creating an electrochemical gradient.
4. Relate to the options: The other terms provided (action potential, depolarization phase, and threshold potential) describe different states or events in the neuron's activity. The action potential is the rapid change in membrane potential during signal transmission, the depolarization phase is a part of the action potential, and the threshold potential is the critical level the membrane potential must reach to trigger an action potential.
5. Conclude: Since the question specifies the stable negative charge of an inactive neuron, the correct term is 'resting membrane potential.' This distinguishes it from the dynamic changes in potential during neuronal activity.